Click advertising payment programs (“pay-per-click”) have become a popular branch of Internet advertising. In the simplest case, the webmaster of the site running the program, here called the Advertiser site, agrees to pay each Affiliate site for each user who clicks through from the Affiliate Site to the Advertiser Site. That is, if a user views a Web page served from the Affiliate Site, and then clicks on a hypertext link (e.g., banner ad, logo, text) in that page to the Advertiser Site, then the Advertiser Site owes the Affiliate Site some predetermined amount of money. The Advertiser Site runs a click-through payment program in order to motivate Affiliate Sites to prominently display ads for the Advertiser Site on its Web pages. Often, the Advertiser Site does not administer such a program itself but rather employs a third-party ad network to administer the click-through program on its behalf.
Click-through counts are also used by the Internet advertising industry at large to determine the effectiveness of a banner ad (its location, design, etc.). Often the click-through rate (i.e., the percentage of users who clicked on the ad after seeing it) is used as a metric to determine the cost of placing the banner ad on a particular Affiliate Site.
As has been recognized in the click-through payment industry, click-through payment programs are susceptible to hit inflation, where an Affiliate Site artificially inflates the click-through count for which it should be paid. Consequently, most ad networks include clauses in their service agreement that explicitly prohibit hit inflation by the Affiliate Site.